package com.itheima.datastructure.priorityqueue;

import com.itheima.datastructure.queue.Queue;

@SuppressWarnings("all")
public class PriorityQueue1 <E extends Priority> implements Queue<E> {
    Priority[] array;
    int size;

    public PriorityQueue1(int capacity) {
        array=new Priority[capacity];
    }

    @Override
    public boolean offer(E value) {
       if(isFull()){
           return false;
       }
       array[size++]=value;
       return true;
    }

    //返回优先级最高的索引值
    private int selectMax(){
        int max=0;
        for(int i=1;i<size;i++){
            if(array[i].priority()>array[max].priority()){
                max=i;
            }
        }
        return max;
    }

    @Override
    public E poll() {
        if(isEmpty()){
            return null;
        }
        int max=selectMax();
        E e=(E)array[max];
        remove(max);
        return e;
    }

    private void remove(int index){
        if(index<size-1){
            //移动
            System.arraycopy(array,index+1,array,index,size-1-index);
        }
        array[--size]=null;
    }

    @Override
    public E peek() {
        if(isEmpty()){
            return null;
        }
        int max=selectMax();
        return (E) array[max];
    }

    @Override
    public boolean isEmpty() {
        return size==0;
    }

    @Override
    public boolean isFull() {
        return size== array.length;
    }
}
